[bombcar]

Which practically ends up the same - see the Etherium fork/rollback.

One potential use maybe would be a blockchain that is openly run by a company (80+% of nodes or something) but if you also run a note it could continue after the company ceases to be.

There are other ways to do that but it might almost be a reasonable use case.

[DarylZero]

You can point to that event but it's actually not enough to establish that it "practically ends up the same."

[stransky]

You can ignore the event, but the trust we’re to put in the blockchain is based on a promise that such an event can’t happen, but it did.

[DarylZero]

Not really. The old chain even still exists.

Also, Ethereum is different from a real blockchain.